Bobbins are used for winding, inter alia, cable, and they can be manufactured in various ways and of various materials. In small sizes, up to about 400 mm, they are in most cases made of plastic or paper. They can be manufactured in one piece or several pieces which are then assembled.
GB-1,303,063 discloses manufacture of a bobbin by bending a plastic channel back on itself so that its ends meet and a cylinder with circumferential end flanges is formed, after which the ends are joined by welding or gluing. The plastic channel is made by extrusion or thermoforming of a plastic strip and is provided with transverse corrugations to allow it to be bent to a cylinder.
The drawbacks of this method of manufacture is that it is time-consuming since manufacture takes place in several steps and different machines or tools are required for each step, and that the corrugation requires a great consumption of material.